The effect of pointlike pinning on vortex phase diagram of Bi 2Sr 2CaCu 2O 8+ δ

Abstract

We numerically examine a possible vortex-matter phase diagram of Bi 2Sr 2CaCu 2O 8+ δ in the presence of dense pointlike defects, by using a Monte Carlo simulation based on the Lawrence–Doniach model. Distinct phases of the Bragg glass, vortex glass, and pancake vortex gas, together with a depinning line within the glass phases, manifest themselves on the field ( B)-temperature ( T) plane. While the locations of these phase boundaries are sensitive to pointlike pinning energy U p( T), we phenomenologically obtain a universal B– T phase diagram depending on a single parameter U p( T). We also discuss the relevance of numerical simulation to recent experiments.